Thermal imaging cameras are used in a variety of situations. For example, thermal imaging cameras are often used during maintenance inspections to thermally inspect equipment. Example equipment may include rotating machinery, electrical panels, or rows of circuit breakers, among other types of equipment. Thermal inspections can detect equipment hot spots such as overheating machinery or electrical components, helping to ensure timely repair or replacement of the overheating equipment before a more significant problem develops.
Depending on the configuration of the camera, the thermal imaging camera may also generate a visible light image of the same object. The camera may display the infrared image and the visible light image in a coordinated manner, for example, to help an operator interpret the thermal image generated by the thermal imaging camera. Unlike visible light images which generally provide good contrast between different objects, it is often difficult to recognize and distinguish different features in a thermal image as compared to the real-world scene. For this reason, an operator may rely on a visible light image to help interpret and focus the thermal image.
In applications where a thermal imaging camera is configured to generate both a thermal image and a visual light image, the camera may include two separate sets of optics: visible light optics that focus visible light on a visible light sensor for generating the visible light image, and infrared optics that focus infrared radiation on an infrared sensor for generating the infrared image.
Thermal imaging cameras may additionally comprise a shutter for use in various applications. Shutters may be used to block incident infrared radiation from the camera's sensing elements, to provide a uniform scene and/or a scene of known temperature to the camera for calibration and/or calculation purposes, such as for non-uniformity correction (NUC). For such purposes, it is often desirable to know the temperature of the shutter. Incorporating a temperature sensor may be costly and may negatively impact other functions of the shutter. Additionally, traditional metallic shutters are easily bent and difficult to maintain as a flat surface. Moreover, such metallic shutters often require a painting process to create shutter surfaces of the proper emissivity.